Ceil construction for roofed vehicles



April 13`, 1937. T. M. y|= Rl.1|: D|-:\\|

GEIL CONSTRUCTION FOR ROOFED VEHICLES Filed Feb. 28, 1936 SWR N NPatented Apr.l13, 1937 UNITED STATES PATENT OFFICE CEIL CONSTRUCTION FORROOFED VE- HICLE 3 Claims.

My present invention relates to vehicle bodies and particularly those ofautomobiles constructed in whole or in part of sheet metal. Suchstructures, particularly in the tops or roofs, while 5 otherwise verydesirable, are subject to the development of annoying noise due to itsaudible vibration. To counteract this, some cars have been engineeredwith acoustic corrective material within the roof to absorb or reducethe Vibration or effects of Vibration within the car. Such materialsbeing generally of a fibrous or like body and often impregnated orsmeared as with asphalt for a stiffening, are unsightly, and necessitatea ceiling lining to make the car interior presentable and attractive.

I have discovered that the ordinary woven head lining as used as aceiling of a car has considerable sound absorption, provided it is drawntautly in its installation. Also, I have found that such head liningshould be spaced away from the roof so that sounds penetrating thelining have an appreciable space to travel before they reach the roof.

I have discovered further that if a head lining is made of a pile fabricthat its sound absorbing properties are increased, and one reason forthis is because its surface is less sound reflecting. However, pilefabrics as made today often have the erected fibres held in place by atightly l woven backing sheet, which construction resists the passage ofsound through the material, i. e. it is relatively sound impermeable.Therefore, I have discovered that if I apply these erected fibres to abacking sheet by a flocking process whereby the short surface fibres areheld erect by a rubber coating applied to the exposed face of the sheetrather than weaving the fibres into the sheet as is customary withordinary pile fabrics such as mohair or plush, and if in addition thebacking sheet is of light Weight open construction, then I have theacoustic benefits of a pile fabric without losingthe sound permeablebenefit of a woven fabric.

There is a further advantage in the use of a piled ceiling material inthat the color of the backing sheet may be covered up by the flockwithout dyeing the backing sheet. In the flocking material described inmy invention it is intended to use libres of relatively short length,perhaps one millimeter in length. These fibres are so short that theywill not of themselves readily hide the color of the underlying backing.Hence, unless some provision is made, this backing is likely to sho-wwhen' the cloth is stretched tautly. 55 I obviate this difficulty bycoloring the bonding cement to match or harmonize with the color of thefibres, which is a very inexpensive thing to do as compared with thecost of dyeing the backing sheet. With pile Woven fabrics such cement asis used is applied to the back side of the cloth and cannot be utilizedin hiding the color of the backing.

As used in this patent by the term acoustic I mean anyacoustic-corrective, such as a sound absorber, a sound insulator or anypanel dampener for reducing audible vibration.

As illustrative of my invention I have shown in the accompanying drawingan indicated embodiment in which I have had shown a metal roofconstruction of an automobile body ceilinged in accordance with myinventionA in its acoustical and screening relation thereto.

In the drawing:

Fig. 1 indicates in section a characteristic metal roof structureaccording to my invention.

Fig. 2 is an indicated magnified section of a ceil in accordance with myinvention, and

Fig. 3 is an enlarged fragmentary section removed at bracket X on Fig.l.

Referring to the drawing I have indicated at I the roof which may be ofany desired construction, that shown being provided with bows orcarlines 2.

To this may be tacked the listing or tacking strips 3 `to which my ceil4 may be attached as by sewing or otherwise attaching.

The interior of the roof cavity thus is defined as a head chamber I0.The interior of the roof l may be acoustically treated as with anasphaltic mixture of vibration dampening character usually containingfibre as suggestively indicated at I l.

The ceil is preferably composed of a flexible backing 4 for which I mayconveniently use a light weight fabric of open weave. Such fabrics areinexpensively available as so-called sheetings or equivalent textileorlike materials.

The surface pores of such a backing provide an excellent anchorage formy bond 5. 'I'his may be a rubber or like cementitious bond adapted toadhere tenaceously to the backing. In this I set my surface flocking offibre 6. These are deposited on and held by the bond in a more or lesserect position. The fiocking may be deposited while the bond is unset,and by agitation or otherwise I cause'the fibres to iiock to stand erectand form a nap-like or pile surface.

The term docking as used herein is to be understood as inclusive ofshort length bres applied in the manufacturing or nishing process ofproducing materials as by sprinkling the bres 10 rative and soundreflection reducing material comprising a exible sheet adapted to betautly drawn over the acoustically treated surface of Such roof interiorin concealing relation thereto, said sheet having cement on its exposedface, and

15 having erected bres ocked on and cemented to said exposed-face.

2. The structure of claim 1, the erected fibres of the sheet being ofinsul'cient length to wholly conceal the color of the bonding substanceon the exposed face of the sheet and the bonding substance being of acolor harmonizing with the color of the erected fibres.

3. The method of reducing the sound in the 1nterior of a vehicle havinga vibratory metal roof, which consists in acoustically treating theinner surface of the metal roof, in coating one face of a exible ceilingsheet with a bonding substance, in flocking erected bres on said coatedface, and in tautly mounting said flocked ceiling sheet within thevehicle in spaced relation to the acoustic treatment of the metal roofand with the flocked face of the ceiling sheet disposed towards theinterior of the vehicle.

THEODORE M. PRUDDEN.

